Google Cloud Storage¶ ↑

Google Cloud Storage is an Internet service to store data in Google's cloud. It allows world-wide storage and retrieval of any amount of data and at any time, taking advantage of Google's own reliable and fast networking infrastructure to perform data operations in a cost effective manner.

Gcloud's goal is to provide a API that is familiar and comfortable to Rubyists. Authentication is handled by Gcloud#storage. You can provide the project and credential information to connect to the Storage service, or if you are running on Google Compute Engine this configuration is taken care of for you.

require "gcloud"

gcloud = Gcloud.new "my-todo-project",
                    "/path/to/keyfile.json"
storage = gcloud.storage

bucket = storage.bucket "my-bucket"
file = bucket.file "path/to/my-file.ext"

You can learn more about various options for connection on the Authentication Guide.

To learn more about Cloud Storage, read the Google Cloud Storage Overview .

Retrieving Buckets¶ ↑

A Bucket is the container for your data. There is no limit on the number of buckets that you can create in a project. You can use buckets to organize and control access to your data. Each bucket has a unique name, which is how they are retrieved: (See Gcloud::Storage::Project#bucket)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"

You can also retrieve all buckets on a project: (See Gcloud::Storage::Project#buckets)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

all_buckets = storage.buckets

If you have a significant number of buckets, you may need to paginate through them: (See Gcloud::Storage::Bucket::List#token)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

all_buckets = []
tmp_buckets = storage.buckets
while tmp_buckets.any? do
  tmp_buckets.each do |bucket|
    all_buckets << bucket
  end
  # break loop if no more buckets available
  break if tmp_buckets.token.nil?
  # get the next group of buckets
  tmp_buckets = storage.buckets token: tmp_buckets.token
end

Creating a Bucket¶ ↑

A unique name is all that is needed to create a new bucket: (See Gcloud::Storage::Project#create_bucket)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.create_bucket "my-todo-app-attachments"

Retrieving Files¶ ↑

A File is an individual pieces of data that you store in Google Cloud Storage. Files contain the data stored as well as metadata describing the data. Files belong to a bucket and cannot be shared among buckets. There is no limit on the number of objects that you can create in a bucket.

Files are retrieved by their name, which is the path of the file in the bucket: (See Gcloud::Storage::Bucket#file)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"

You can also retrieve all files in a bucket: (See Gcloud::Storage::Bucket#files)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
all_files = bucket.files

Or you can retrieve all files in a specified path:

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
avatar_files = bucket.files prefix: "avatars/"

If you have a significant number of files, you may need to paginate through them: (See Gcloud::Storage::File::List#token)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"

all_files = []
tmp_files = bucket.files
while tmp_files.any? do
  tmp_files.each do |file|
    all_files << file
  end
  # break loop if no more files available
  break if tmp_files.token.nil?
  # get the next group of files
  tmp_files = bucket.files token: tmp_files.token
end

Creating a File¶ ↑

A new File can be uploaded by specifying the location of a file on the local file system, and the name/path that the file should be stored in the bucket. (See Gcloud::Storage::Bucket#create_file)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
bucket.create_file "/var/todo-app/avatars/heidi/400x400.png",
                   "avatars/heidi/400x400.png"

Downloading a File¶ ↑

Files can be downloaded to the local file system. (See Gcloud::Storage::File#download)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"
file.download "/var/todo-app/avatars/heidi/400x400.png"

Using Signed URLs¶ ↑

Access without authentication can be granted to a File for a specified period of time. This URL uses a cryptographic signature of your credentials to access the file. (See Gcloud::Storage::File#signed_url)

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"
shared_url = file.signed_url method: "GET",
                             expires: 300 # 5 minutes from now

Controlling Access to a Bucket¶ ↑

Access to a bucket is controlled with Gcloud::Storage::Bucket#acl. A bucket has owners, writers, and readers. Permissions can be granted to an individual user's email address, a group's email address, as well as many predefined lists. See the Access Control guide for more.

Access to a bucket can be granted to a user by appending +“user-”+ to the email address:

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"

email = "heidi@example.net"
bucket.acl.add_reader "user-#{email}"

Access to a bucket can be granted to a group by appending +“group-”+ to the email address:

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"

email = "authors@example.net"
bucket.acl.add_reader "group-#{email}"

Access to a bucket can also be granted to a predefined list of permissions:

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"

bucket.acl.public!

Controlling Access to a File¶ ↑

Access to a file is controlled in two ways, either by the setting the default permissions to all files in a bucket with Gcloud::Storage::Bucket#default_acl, or by setting permissions to an individual file with Gcloud::Storage::File#acl.

Access to a file can be granted to a user by appending +“user-”+ to the email address:

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"

email = "heidi@example.net"
file.acl.add_reader "user-#{email}"

Access to a file can be granted to a group by appending +“group-”+ to the email address:

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"

email = "authors@example.net"
file.acl.add_reader "group-#{email}"

Access to a file can also be granted to a predefined list of permissions:

require "gcloud"

gcloud = Gcloud.new
storage = gcloud.storage

bucket = storage.bucket "my-todo-app"
file = bucket.file "avatars/heidi/400x400.png"

file.acl.public!